Technical Abstract:
There are numerous industrial applications for durable hydrogels including the use in hydrogel-based lightweight concrete. Starch-based hydrogels are inexpensive and durable but are not stable in alkaline environments. Hydrogels made of blends of starch and magnesium silicate had greater stability in alkaline conditions than hydrogels made only of starch. Blends of starch and 30% poly(vinyl alcohol) had the highest alkaline stability. The starch/poly(vinyl alcohol) blends also had the greatest moisture content of the hydrogel formulations tested. Blends of starch with 5, 10, 20 and 30% poly(vinyl alcohol) were made to determine the least amount of poly(vinyl alcohol) needed to provide adequate resistance to alkaline conditions. Blends of starch and ethylene (vinyl alcohol) copolymer were tested for a comparison with the starch/PVOH blends. The results showed that hydrogels made of starch/polymer blends have adequate shear strength and provide alkaline stability needed for hydrogel-based lightweight concrete.